01-26-2009, 09:05 PM

Hello, I am new to installing ram but I have seen it done many times. I just bought 4 gigs of ram to install into my mac pro. My mac pro came with 2 gigs of the apple ram. I was wondering if I have to take out the apple ram and replace it with the other brand or am I able to add onto it for a total of 6 gigs? thanks.

01-26-2009, 09:13 PM

Originally Posted by bazerc

Hello, I am new to installing ram but I have seen it done many times. I just bought 4 gigs of ram to install into my mac pro. My mac pro came with 2 gigs of the apple ram. I was wondering if I have to take out the apple ram and replace it with the other brand or am I able to add onto it for a total of 6 gigs? thanks.

The Mac Pro has 8 memory slots. If you have 2 gigs of ram currently...the worse case scenario is 512mb x 4...so only 4 memory slots occupied, thus 4 slots still empty.

If you purchased 4 x 1 gig memory...no problem...you have 4 empty slots. If you bought 2 x 2 gig of memory...that would only be 6 memory slots filled (existing memory + new memory)...and thus two empty slots remaining.

Maybe I'm missing something (maybe you need to provide more detail)...but this seems like a "no-brainer" to me (no need to remove any memory)!

- Nick

01-26-2009, 09:21 PM

Sorry, I have 2 GB of apple ram (1GB is on riser A and the other 1GB is on riser B) I ordered 4GB which comes in 2x2. If I added everything I would only be using up 4 slots. I am fully aware of how much room I have but my main concern was am I able to mix different brands of ram? thanks.

01-26-2009, 09:32 PM

The brands or RAM don't matter (unless its Yinkletonk or some cheap weird type) as long as they're the right specs and matched pairs, which the Mac Pro requires.

So, you have a matched pair of 1 Gb (2 slots) already in place, and now one matched (hopefully) pair of 2 Gb (two slots). Whack them in next door to the existing RAM, boot your Mac Pro and see what Sys Profiler has to tell you. Post back if either failed - or successful!

01-26-2009, 09:32 PM

Originally Posted by bazerc

Sorry, I have 2 GB of apple ram (1GB is on riser A and the other 1GB is on riser B) I ordered 4GB which comes in 2x2. If I added everything I would only be using up 4 slots. I am fully aware of how much room I have but my main concern was am I able to mix different brands of ram? thanks.

It sounded to me like you weren't sure if you needed to remove old ram to make space for the new ram.

In any case...mixing brands of ram is done all of the time. As long as the ram you're installing is guaranteed to work in a Mac Pro.

If that is the case...you should have no problems.

Good luck,

- Nick

01-26-2009, 09:35 PM

Perfect, thanks alot for the replies.

09-16-2009, 02:16 PM

Similar question so I hope you don't mind me tagging onto your post!

I have a Mac Pro (Dec 07) and have discovered I have 4 x 1GB of DDR2 FB-DIMM 667 MHz

They are installed in Riser A and B in DIMM1 and DIMM2 respectively.

So, I haven't opened it up to look at this point btw.

I want to upgrade a much as my wallet will take and I've found some same spec ram 4 x 2gb RAM for £160

So, do I just install these in the other 4 slots remaining? Or do I need to move things about to keep "matched pairs"

Thanks in advance

09-16-2009, 05:52 PM

Keep them in matched pairs as set out in the user guide. If you do not, on reboot the fans will go like crazy and you will get the three beeps indicating faulty, improperly fitted or no memory modules.

09-17-2009, 03:28 AM

How do I know what constitutes a "pair" so to speak? I understand that the 1gb should stay together as pairs as should the 2gb ones. However, what constitutes a pair in the slots? Based on the fact the existing memory is installed in Riser A & B in DIMM's 1 & 2 does this mean I have have DIMM's 3&4 empty on Riser A & B? IN which case do I simply install the remainin 4 x 2gb in DIMM's 3 & 4 in Riser A&B? Sounds logical!

Thanks once again

09-17-2009, 06:41 PM

The SDRAM DIMMs must be installed in pairs with one DIMM per bank.

DIMMs are already installed in these two slots. Install additional DIMMs in these two slots first.

If slots are available, and you want to install more memory, install additional DIMMs in a similar fashion: In pairs, one per bank, from the center outward.

This is from the service manual. A pair is a matched pair, say 2x2GB modules same brand and specs. Hope it helps!